UV-C: An Introduction to Ultraviolet (UV) Light

It is very important to know that UV Light exist all around us. Generated by the sun, it is a part of the spectrum of electromagnetic energy. This spectrum consists of other form of energy such as radio waves, infrared, visible light, x-rays, gamma rays and cosmic rays. Since UV is not visible, it is technically not a “light”!

Discovery:

The discovery of UV radiation was intimately associated with the observation that silver salts darken when exposed to sunlight. In was in the 1801 that German physicist Johann Wilhelm Ritter made the observation that invisible rays just beyond the violet end of the visible spectrum were especially effective at darkening silver chloride-soaked paper.
The term "chemical rays" was adopted shortly thereafter, and it remained popular throughout the 19th century. The terms chemical and heat rays were eventually dropped in favor of ultraviolet and infrared radiation, respectively.

It was not until 1950’s that the connection and effect of sun’s rays on the human tissue was discovered. An artificial sunlight known as the Finsen Curative lamp which contained ultraviolet (UV) rays was then developed. This lamp has been used as a sterilizing aid throughout the late 1950’s.

The key portion of the discovery was that (UV) light has the ability to destroy pathogenic organisms.

What are the type of UV Light exist?

UV-A:
“Longwave” UV also known as blacklight, the major type of UV in sunlight, responsible for skin tanning.
UV-A is harmful and it is used to treat certain type of skin disorders.

UV-B:
It is a small part of the sunlight and dangerous. Most of it is being blocked by the ozone layer. Long exposure to the sun can enable UV-B  responsibility for skin cancer, skin aging and cataracts.

UV-C:
“Short-wave” UV and it is not present in the sunlight. It also includes germicidal UV (253.7nm wavelength) used for air disinfection. If unintentionally overexposed it can cause transient skin redness and eye irration. UV-C do not cause skin cancer or cataracts.

UV “Kill” Airborne Pathogens?

UV-C reacts with cell DNA, causing alterations which result in organism self-destruction. Any form of organism that the UV-C is able to penetrate will be killed. This of course is dependant on time, exposure and intensity of the UV-C rays. UV-C rays do not have great penetrating abilities into most substances. Penetration is ineffective on “solid” surfaces. Organism visible to the naked eye are usually too large and therefore too resistant to be killed. It may take 10 to 100 times the intensity to kill them.

The UV-C “Killing Factors” are based on:

1. The intensity of UV radiation.
2. The length of time or exposure to the UV radiation.
3. The relative humidity.
4. The air temperature.
5. The microbial species.

The safe level of UV exposure and installation are still needed to be handled by experts or those who have experience in installing UV-C type products. This is because exposed UV-C rays can cause eye irritation. Every UV-C products need to meet the NIOSH standards before being used or marketed.

However now, Soma Medical Sdn. Bhd. has a range of UV-C based products that works effectively on almost all type of surfaces. The UV-C lamps are better handled and optimized for any range of environment and situation. Click here for the type of products available.

Contact us for more information.

Researching UVGI?  You'll find government studies and guidelines for the use of UVGI below.